Event Item Trading
The Event Items are items which Link can exchange at certain places. If Link shows the right item to the right person, he can swap that item for a different one. Keep swapping the items during the adventure for something good.
YOUNG LINK'S EVENT ITEMS
The Event Items Link trades in his youth centre around the Happy Mask Shop in Hyrule Town. Win the favour of the Mask Shop Owner by selling as many masks as possible.
Weird Egg: This is first Event Item you obtain. Get caught by the guards at Hyrule Castle and Malon will now be near the entrance to the grounds. Offer to find her father and Malon will give you this Egg; it will hatch overnight into a Cucco.
Cucco: A chook which hatches overnight from the Weird Egg. Use it to wake Talon somewhere near Hyrule Castle, so that he can get back to Lon Lon Ranch.
Zelda's Letter: After you meet with Princess Zelda at the Castle Courtyard, she will give you a letter with her signature on it to help you during your adventure. Show it to the guard at the start of the Death Mountain Trail and he will open the gate for you.
All of the following Event Items are obtained from the Happy Mask Shop. Select your Mask and the Mask Shop Owner will lend it to you in the hopes that you can sell it. Show off the Mask by pressing C, then talk to people to hear their reactions. If you show it to the right person, they'll offer to buy it from you. After you make the sale, return to the Happy Mask Shop and repay the marked price. You will now be able to borrow a new Mask.
Keaton Mask: There's a children's character called Keaton who's a very popular guy among the Hylia. Sell this Mask to the guard the Death Mountain Trail start, who wants to buy it for his son. You make a five Rupee profit on the sale.
Skull Mask: This monster-shaped Mask is one of the totems amongst the outcasts within The Lost Woods. Sell it to the lone Skull Kid in the Lost Woods, but you make a 10 Rupee loss. To find the buyer, enter the Lost Woods from Kokiri Forest and turn left. Note that you must play Saria's Song to him first, in order to show you're a friend.
Spooky Mask: A misery-inducing wooden mask, which will scare the living daylights out of small children and stray dogs. Sell this mask at cost price to the boy who patrols the Kakariko Village Graveyard during the day.
Bunny Hood: This is perhaps the hardest item to sell, simply because the buyer patrols such a large area. You sell this mask to the Marathon Runner, and the easiest way to find him is to enter Hyrule Field from Kokiri Forest, then travel south and wait at the end of the path. Eventually he'll stop for a rest, at which time you can sell him the mask. Selling this mask fills your current wallet, but remember you must still pay back 50 Rupees.
After you sell the Bunny Hood, four new masks become available: Gerudo Mask, Goron Mask, Zora Mask and the Mask of Truth. The first three have no real value other than a bit of fun, but the Mask of Truth is the most important. Wearing this Mask, you will be able to talk to the Gossip Stones which litter Hyrule. This can enable you to get a hint for the game, or just give you an interesting tidbit of information about the land of Hyrule.
ADULT LINK'S EVENT ITEMS
Adult Link's trading run involves a series of errands and returning certain items to their respective owners. On the map, a red arrow will appear pointing you to the next place you must visit in order to get the next item.
Pocket Egg: This is the egg of a new breed of mini-chook. It will hatch overnight into a Pocket Cucco.
Pocket Cucco: Dampé's sister wants this chook in a happy mood when you return it to her. Wake up Talon, who's sleeping at Kakariko Inn, to make the chook happy. Return the Pocket Cucco to Dampé's sister.
Cojiro: A blue (??) chook, which rarely crows after the death of its owner. Exactly what purpose this chook has I don't know, but you can show it to the Chief Carpenter's Son to convince him you're a nice guy. Which is a good thing, too, because the fool has entered The Lost Woods! Find him by entering the woods from Kokiri Forest and turning left.
Odd Mushroom: A rare forest fungus which the Chief Carpenter's Son has found. If added to various potions, its effects can be a help or hinderence. The Chief Carpenter's Son wants you to take this to Granny at the Potion Lab in Kakariko Village, but the Mushroom will spoil before too long. You have three minutes to reach Kakariko Village; you can make it, even without Epona. Though you can't use the Nocturne of Shadow, you can use the Sun's Song if you reach the village during the night.
Odd Potion: Granny asks you to deliver this to the Chief Carpenter's Son after you give her the Odd Mushroom, but by the time you reach him the magic of The Lost Woods would have claimed the poor boy. Fado is in his place, and in exchange for this potion she will give you the Chief Carpenter's Saw.
Poacher's Saw: This actually belongs to the Chief Carpenter, and its exact movements over the past few days are rather difficult to track: the Chief Carpenter said he left it with Granny, but somehow the Chief Carpenter's Son gets his hands on it! Cross the main bridge at Gerudo Valley with Epona or the Longshot to obtain this.
Broken Goron's Sword: The cheapskate Chief Carpenter gives you this for returning his saw. Biggoron, who is at the summit of the Death Mountain Trail, is the only craftsman skilled enough to repair it. Unfortunately, his eyes have been irritated from a recent eruption of Death Mountain and he is unable to do it.
Perscription: For Biggoron to repair the sword, you must get him some eyedrops. The best place for eyedrops is Zora's Domain; thaw King Zora from the Red Ice and show him the Perscription.
Eyeball Frog: King Zora can only give you the ingredients necessary for Biggoron's eyedrops, and they won't last. You have three minutes to reach the Lakeside Lab at Lake Hylia to have the eyedrops made; you must have Epona to make it.
World's Greatest Eyedrops: The trick behind these drops is their lack of preservatives. You have four minutes to get from the Lakeside Lab to the end of the Death Mountain Trail; to get there, you must have Epona and use the Magic Plant near the entrance to Dodongo's Cavern. Deliver the goods fresh and Biggoron will get back to his blade business.
Claim Check: It will take Biggoron three days to make his blade. Wait if you like, or just play the Sun's Song six times for very much the same effect. Show the Claim Check to retrieve your prize, and you'll be able to keep this as a momento.